testsuite: Fix up gomp/simd-{2,3}.c tests [PR98243]

testsuite: Fix up gomp/simd-{2,3}.c tests [PR98243]

The test (intentionally) is not gcc.dg/vect/, as it needs -fopenmp and uses
OpenMP directives other than simd and therefore can't rely on default
VECTFLAGS and so I think can't safely use vect_int effective target
either.  So, I'm just making sure it is vectorized on x86 and on aarch64 (the
latter as an example of a target that doesn't need any extra options to get
the vectorization).

2021-01-30  Jakub Jelinek  <jakub@redhat.com>

	PR testsuite/98243
	* gcc.dg/gomp/simd-2.c: Add -msse2 on x86.  Restrict
	scan-tree-dump-times to x86 and aarch64 targets.
	* gcc.dg/gomp/simd-3.c: Likewise.